Contents
How is inverse variance calculated in a meta-analysis?
Inverse variance meta-analytical methods involve computing an intervention effect estimate and its standard error for each study. For studies where no events were observed in one or both arms, these computations often involve dividing by a zero count, which yields a computational error.
What kind of Statistics are used in a meta-analysis?
The two summary statistics commonly used for meta-analysis of continuous data are the mean difference (MD) and the standardized mean difference (SMD). Other options are available, such as the ratio of means (see Chapter 6, Section 6.5.1 ).
Why are some studies excluded from a meta-analysis?
The standard practice in meta-analysis of odds ratios and risk ratios is to exclude studies from the meta-analysis where there are no events in both arms. This is because such studies do not provide any indication of either the direction or magnitude of the relative treatment effect.
How is a fixed effect meta-analysis calculated?
A fixed-effect meta-analysis using the inverse-variance method calculates a weighted average as: where Yi is the intervention effect estimated in the ith study, SE i is the standard error of that estimate, and the summation is across all studies.
How is a meta-analysis similar to a normal regression?
A meta-regression analysis is similar to a normal regression analysis, except that the heterogeneity between studies is modeled. This process involves performing a regression analysis of the pooled estimate for covariance at the study level, and so it is usually not considered when the number of studies is less than 10.
Do you do a meta-analysis in a systematic review?
Do not do a meta-analysis. A systematic review need not contain any meta-analyses. If there is considerable variation in results, and particularly if there is inconsistency in the direction of effect, it may be misleading to quote an average value for the intervention effect.